The Liar's Paradox
The liars paradox is best illustrated with a piece of paper, written upon it the line "this sentence is false". (now follow along) So if the line, "this sentence is false", is true, then it is indeed false; however, if the sentence claims that it is false, then it must truly be false. Though if it's false... then it must be true. And there within lies the paradox; it's an ongoing contradiction of conclusions formed by illustrating the common belief about what true and false actually means, and even though the phrase is completely in accordance with grammatical rules, there is no value to determine absolute truth.